Hydraulic bag loader for vehicles



HYDRAULIC BAG LOADER FOR VEHICLES Filed July 9. 1952 2 Sheets-Sheet 1 ATTORNEY March 27, 1956 J, H, MACKANESS ETAL HYDRAULIC BAG LOADER FOR VEHICLES Filed July 9, 1952 2 Sheets-Sheet 2 IN VENTORS JOHN H. MACKANESS JOHN H. MORLING United States Patent *f 0 "e 2,739,719- l HYDRAULIC BAG-Lonnnnronvnnrcaus John H. Mackaness and John H. Morling, Bill-ing, Northampton, Englandl Application JulyA 9, 1952, Serial No. 297,816 Clamspriority, application Great Britain-July 19, 1951 9 Claims. ((1214-77) This invention relates to hydraulic bag loaders of the knowntype, which, briefly, comprises a bag-supporting cradle, the inner `end of whichis pivotally mounted upon a. vehicle, a hydraulic cylinder pivotally carried by, and below, the vehicle oor structure, and a piston slidable inthe cylinder andhaving a rod which is attached by a cross-head `to the cradle.

Inth'e known bag loaders of this type liquid is pumped into the cylinder `by .means of a pumpl on the vehicle and when the cradle is in its lowered position and a bag is not mounted upon it, the piston then being in its innermost. position in the cylinder, the liquid is circulated idly inthe cylinder through an open control valve. A flexible strap is arrangedlengthwise upon the cradle and is coupled to the valve through lever and chain mechanism,

the arrangement being such that when the bag is laid on the cradle it' presses the strap downwards andthe valve is closed,`,whereupon the pressure liquid forces the piston outwards in its cylinder and ythe cradle is swung upwards into the loading position.

When the cradle has reached the loading position the piston uncovers a port in the cylinder and the liquid is again circulatedthrough a return pipe from the pump through the cylinder, the control valve still being closed. As soon as the bag is removed from the cradle, however, the strap ilexes outwards and the valve is opened, whereupon the piston moves inwards and the cradle is automatically lowered.

Suchl a hydraulic `bag loader has several disadvantages. In particular, it is not a simple matter to remove the cradle from the vehicle, since the piston rod has to be uncoupled from the cradle-and the-pivoted cylinder has to be'locked against swingingdownwards by means provided forthat purpose. Thereafter, the means whereby the cradle is pivotally attached to the vehicle have to be removed. For this'reason, when not in use, the cradle is'usuall-y locked "in-a' fully elevated position.

Afurther disadvantage of-sucli apparatus is'that owing to l-the fa'ctthat the-lstrapdensioning' spring is located 'adjacent the hydraulic operating-meansin a more or less inaccessible-positi'on` a strap `or chainof considerable length iserequiredand issonl-y with dimc'ul-ty removable for replaeementlorrepair `or when -they cradle is detached.

The present invention has the advantagef-that'itsimplifies the attachment of the cradle to the vehicle and permits of its'ready'vand `easy-removal. It obviates the use of supportingf-bracketsxorstays fondue-.cylinder when the apparatus is not in use. Further, the cylinderis so mounted vthat-it yis maintained yin a balanced position `when the apparatus is not in use andthe cradle has been removed.'`

According to the present invention therefore there is provided an hydraulicJ bag loaderofithe type referred to whereirntheahydraulicjuid cylinder is fadapted to be pivdtallylmountedonathe vehicle. `artnet-end of thefcylinder retriote from the end -at which fthe'-pis'ton is located-when in its innermost position, the cylinder being retained v 2,739,719 Patented Mar.

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2j against downward l swinging movement without vthe 1 use of retention means when the piston rod is uncoupled from the-cradle.

The cylinderlis preferably carried by two'spaced-"tifun"W niony mountingsl-including -Ibearings provided 10u' two --downwardlyz-extending brackets carried on thel underside-ofthe vehicle floor-supporting structure.A

Means are also `provided A.for #detachabl-y' vattaching lthe inner endI of'th'e cradle-'to' the-vehicle and-fsuch means conveniently consist y-of"lin`lrs orrstraps whichi -a'retpivot'ally` suspended from the'4v chassis lstructure -at their upperiends and are provided-iat their' ylowerV ends withikoperr seatings in which lis engaged across shaft AuponYwhichacross-head at .the outer end of i the -pistonrod is fpivotally; mounted. vBoth .ends -of each link `or straparel preferably of hook vformation and-thevvehicleor 'in-ner ends of upper-structural members of `the cradle "are-atta'chedto the upper hooked ends of the linksor-straps, while lower's'tructurallfmeirrbers =are attached to the lower 'hooked l:ends lor seatings. The-arrangement is suchthatthe upperv ends mayy be detachab'ly and -pivotally suspended i from -the saidl cross shaft while they lower ends forml open-*seati-ngsfwhich 'are pressed against the cross-:headshaft' under'th'eweight vof the cradle or-of thelatter-andfthe-bag- In orderthatfthe-inventionimay be 1nore-clearly understood therefwill-nowl bedescribed ybyy wa-yt of-example one particular forni of `hydraulicbag loader which is illustrated-fin-ithe accompanying drawings, in which:

Figur-.e 2"is-an-enlarged end ielevationa-l View from-the directionoflthearrow of-fFigure'lfl;

Figure 3 is a fragmentary side-view of-tlrefinneror connectible-'end'fof -the bag* loading cradle; l

Figure 4'isv-a-fplannviewofthe-cradle actuator; tl-latiis toV be -securedlto-'ftheunder rear portion of a-vehic'le as shown infigure- 1,. )witlhl -th'e cradle=omitltedg and Figure '5 iis i anlongitudirlal secional tview of l'the-actuator shown-in Figure ti-and takensub'stantially upon linel S--S of F i gure-4- Thel cradle consists -in known manner, of `a 'framework l-offinter-connected barsfor tubes, the outer-endiparts of thelupperbarsfor tubesfZ-beingshaped -tov carryv a bag. Tlief-end of Seach pairof Ith'ese; two t longitudinal baarsy yor tubes 41 fand Zisattachedtoaplatelink =4 f-whiclr -is curved over fat its :upperendawayufrom the cradle to "form hook 4a` of'- across-section slightly4 greater than axsemi-circle. The lower` endy of each'platevlink 4 is also.- curved @to 4forrn a` seatingr4bwhich faces awa-yA fromthefcradle and is of substantiallyserni-circular section.v v

Th'e hydraulic cylinder `5 .is provided on `opposite sides witlr-twoico-axialdtrunnionsilwhicharelocatedfclose---up tofthat end of' the cylinderwhich' is remotewfromrthe end occupied.' by the pistonf-7'1whenithe latterf isz at '-theain'ner end-*oi its Strokervv Eachf ltrunnio'nv 'fis -pivotallyrmounted Pin: a--bearin'gff 6a provided on a downwardly-extendingccheek.plate bracket 8,- th'etwo fbra'ckets 8`fb`eing scour-edf tot; two-j` anglersupports9xed 5to thef undersid'erof the l'vehicle floor structure'. Two'v co-axial ho'llowfb'os'ses 210 are providedon Vopposite sides :ofeachplatesbracket!8 2c1osetupf toztheiunderside carried 2in1 bearings A providedir'r the/two sets of bosses.

A hollowcross-headdz fisadjustab1yfnxed-tothe outer end otiithevpistorrA rod? liliand' Ehas l afcross-fhead' shaft'.- 13 extending` laterally vthere'ir'o'niiat 1 opposite# sideii thereof. Tliel-cross-h'ead shaft 13l'1is ipa'rallellto' theabovementioned cross shaft f 11i andi is'-` pivotallyv suspended@ therefrom: at itsV opposite-1 endsi by rigid. links;v 16' The cross-head 152 is screwed upon the piston rod 14 andflmayifbel-lockeduin variousradiustediposisionscbyarlocknut-Llss.

When the loader is to be used the upper ends 4a of the i two plate links 4 are hooked over the cross shaft 11 (see Figures l and 2) and the curved lower ends or seatings 4b are engaged over the cross-head shaft 13, with which they are maintained in contact under the weight of the cradle. f

In order to detach the cradle it is only necessary to disengage the two seatings 4b from the cross-head shaft 13 and to lift the upper hooked ends 4a olf the cross shaft 11.

The cylinder is then held steady in an inclined position without the use of retention means, and does not swing downwards about its trunnion bearings. rfhis is by reason of the pair of suspension links 16 which extend between the cross shaft 11 and the cross-head shaft 13 and maintain constant centres for the easy attachment of the cradle, and the friction and (or) pressure on the piston 14 and rods. Without the links 16, the cylinder 5 would be free to rotate on its trunnions and so fall to a vertical position, but by means of the links 16 the amount is limited by the radius of the links, sol that should the friction or pressure be non-existent the cylinder could never fall beyond the radius as for normal working positions. It has been proved in practice that no movement of the cylinder 5 in fact takes place, because after the removal of the cradle residual pressure in the cylinder, together with the friction of the piston gland 14a, are more than sufficient to retain the weight of the cylinder.

The loader is operated by means of a hydraulic pump (not shown) driven from the vehicle or by a separate power unit, if required, the huid being pumped along a ilexible tube 17 into one of the trunnions 6 whence it passes through a three-way valve or plug cock 18 at the pivoted end ofthe cylinder and along a tube 19 to the end of the piston, when the latter is in the working or raised position, and through a return tube 2i) when the apparatus is in the resting or lowered position back to the pump supply cylinder or tank.

When a bag or other load is placed on the distal end of the cradle, it depresses a strap 21 extending longitudinally of the cradle and connected to anend of a slotted draw bar or link 22 through which the vcross shaft 11 extends and serves as a guide and retaining member therefor. The other end of the draw bar 22 is connected to one end of a lever 23, pivoted at 23a intermediate itsends, by a helical tension spring 24 and the other end of the lever is connected by a link 25 to a laterally extending arm 26 fast on the rotatable stem 18a of the valve 18. When the strap 21 is depressed, the spring 24 is thereby stretched or extended and, through the linkage just mentioned, operates the plug cock valve 18 to admit hydraulic pressure from the pipe 17 through the pipe 19 to the piston head 7, causing the latter to move, from its position indicated in Figure 1, toward the pivoted end of the cylinder 5, whereby the cradle is raised to a vertical position (shown in dotted lines in Figure 1) in which the bag is at shoulder height with respect to an attendant on the vehicle. When the piston has reached the limit of its movement toward the pivoted end of the cylinder S, a spring loaded valve 27 on the piston is then opened and the uid is free to pass therethrough to a return tube or pipe line 20 for as long as the piston is fully extended.

When the bag or load is removed from the cradle, the tension spring 24 is relieved of the tension which had been imposed thereon and the valve stem 18a is rotated in an opposite direction by a return spring to cut-o the hydraulic pressure to the piston head 7. This return spring may be a helical tension spring 28 connected at one end to a suitable fixed bracket 29 and at its other end to a second arm 30 extending laterally from the valve stern 18a. The contraction of the spring 24, by reason ofthe load being relieved from the tape or strap 21, draws back the draw bar 22 so as to take up the slack in the strap 21 and the cradle falls by gravity to the down position ready for the next operation. U

An advantage of this arrangement 1s that by reason of the mounting of the draw bar 22 on the cross shaftand the connection therewith of the return spring only a relatively short strap is required, such a strap being readily attachable and detachable as by means of a snap hook as shown, as required.

.lt should be understood that the hydraulic bag loader which has been described is illustrative only of the invention various rnodlications` within the scope of the appended claims being possible.

We claim: 4

l. An hydraulic bag loader ofthe type for vehicles comprising a hydraulic liuid cylinder pivotally mounted on the vehicle at the end of the cylinder remote from the end at which the piston is located when in its' innermost position, a load supporting cradle, detachable means pivotally connecting the cradle to the vehicle for swingmovement relative to the vehicle, and further means detachably connecting the cradle to the piston rod of the cylinder to impart movement to the cradle, the cylinder being retained against downward swinging 'movement about its pivot without the use of retention means, when the piston rod is uncoupled from thercradlc. 'i

2. A11 Ahydraulic bag loader in accordance with claim l in which the cradle is detachably supported by means of at least one link member which is pivotally suspended from the vehicle by its upper end with its lower end seated against the piston cross-head shaft.- n i 3. An hydraulic bag loader in accordance with 'claim l including a pair of link members secured to one end of the cradle, the upper ends of the link members being shaped to hook over a shaft on the vehicle and the lower ends of the link members being shaped to seat against the piston cross-head shaft so that outward move'- ment of the piston towards the pivoted end of the cyl inder causes the cradle to swing about the upper ends ot' the link members into its raised or working position.

4. An hydraulic bag loader in accordance with 'claim 3 including means extending between the suspensionshaft and the cross-head shaft for ensuring correct radial separation of these shafts and facilitating attachment of the cradle. r

5. An hydraulic bag loader in accordance with claim 4 wherein said means consist of a pair of suspension links which are also effective to limit any downward swinging movement of the free end of the cylinder.

6. An hydraulic bag loader in accordance with claim l wherein the hydraulic cylinder is provided with'htruw nions which are mounted in bearings on downwardly extending brackets secured to the vehicle.

7. An hydraulic bag loader in accordance with claim 6 wherein the suspension shaft for the cradle extends between the said brackets and is supported thereby.L

8. An hydraulic bag loaderr in accordance with claim 7 including a slotted draw bar mounted on the suspension shaft for transmitting movement of a flexible strap on the cradle to the means for controlling the ow of hydraulic fluid to the cylinder.

9. An hydraulic bag loader in accordancek with claim 8 wherein a spring is connected with the draw bar which is thereby effective to take up the slack in the exible strap when the cradle is unloaded.

References Cited in the tile of this patent 256,991 Switzerland May 4, 1946 

